Storage subsystems, such as magnetic tape libraries, are widely used for storing information in digital form. An exemplary tape storage subsystem 100 is shown in FIG. 1. These tape subsystems 100 may include a storage subsystem controller 101 for controlling one or more tape drives 102 contained within the storage subsystem 100 and for controlling other components of the storage subsystem 100, such as the tape picker, which is used to select and load tape cartridges 106 into the tape drives 102. The storage subsystem 100 may be coupled to a host system 110, which transmits I/O requests to the storage subsystem 100 via a host/storage connection 112.
The tape drive 102 reads and writes data to the primary storage medium, shown in FIG. 1 as a magnetic tape medium 104 contained within a removable magnetic tape cartridge 106. The magnetic tape medium 104 typically comprises a thin film of magnetic material, which stores the data. The tape medium 104 may be moved by the tape drive 102 between a pair of spaced apart reels and past a data transducer to record or read back information. In one type of tape drive system, one of the reels is part of the tape drive 102 while the other reel is part of the removable tape cartridge 106. For this type of tape drive system, the reel which is a part of the tape drive 102 is commonly referred to as a take-up reel, while the reel which is a part of the tape cartridge 106 is commonly referred to as a cartridge reel. Upon insertion of the tape cartridge 106 into the tape drive 102, the magnetic tape medium 104 on the cartridge reel is coupled to the take-up reel of the tape drive 102. Subsequently, prior to removing the tape cartridge 106 from the tape drive 102, the storage tape 104 is rewound onto the cartridge reel and is then uncoupled from the take-up reel.
In some tape storage subsystems, the removable tape cartridge 106 is provided with a non-volatile auxiliary memory 108 for storing data in a separate storage medium from the primary storage medium. This data is separate from and in addition to the data stored on the primary storage medium. This auxiliary memory 108 can be, for example, a solid state non-volatile memory such as an electrically erasable programmable read-only memory (EEPROM) or a flash memory which is contained in the housing for the tape cartridge 106. One standard being proposed for incorporating and using such an auxiliary memory in a tape cartridge is referred to as “Medium Auxiliary Memory” (or MAM). This proposed standard is described in “Working Draft SCSI Primary Commands-3 (SPC1-3)”, Project T10/1416-D, Revision 13, dated May 16, 2003, incorporated by reference herein in its entirety. In addition, the information described in U.S. provisional patent application Ser. No. 60/475,679, and entitled, EMULATION OF AUXILIARY MEMO MAGNETIC TAPE MEDIA, is incorporated herein by reference in its entirety as if fully set forth herein.
Further, in storage systems having tape cartridges (with or without auxiliary memory) various read/write errors may occur that originate with the tape cartridge, the tape drive, or a combination of both. When errors occur it may not be evident if the errors are a result of the tape drive or the tape cartridge making corrective or predictive action difficult.
Therefore, in various storage environments including tape cartridges and tape drives it is desired to be able to diagnose errors and manage tape cartridges and tape drives to determine the cause or likely cause of errors and manage and/or predict future errors in the system. Such a management system may allow one to take preventive measures and manage the system with reduced error rates and increased efficiency. Thus, the ability to determine where errors are likely to occur, monitor utilization of particular tape drives or tape cartridges in a storage system, and take corrective measures to ensure the reliability and security of the tape storage environment are desired.